1. Field of the Invention
The present invention relates to a sheet feeding device including a unit drawer device where a unit is mounted on a device main body so as to be drawn from the device main body, and an image forming apparatus that includes the sheet feeding device.
2. Description of the Related Art
For example, a copying machine, which is an image forming apparatus, generally has a function to read out an image of a document or the like, and forms an image on a sheet based on the read image information. However, in recent years, there is a copying machine that has a communication function or the like and a function to input image information to be sent from the outside. Further, a printer, which is an image forming apparatus, forms an image on a sheet based on image information that is generally sent from an external device, for example, a computer or the like.
A sheet feeding device, which feeds sheets to an image forming portion, is disposed at a lower portion or middle portion of an apparatus main body of each of these image forming apparatuses. The sheet feeding device includes a sheet storage portion as a unit and a sheet feeding portion that feeds sheets stored in the sheet storage portion. In general, after the sheet storage portion is drawn from the apparatus main body, the sheets are stored in the sheet storage portion.
Among these kinds of image forming apparatuses, there is an image forming apparatus that includes a unit drawer device for drawing a sheet storage portion. The unit drawer device includes a pressing operation member (button) that is pressed when the sheet storage portion is drawn from the apparatus main body, and a locking mechanism that locks the sheet storage portion to the apparatus main body. Further, the lock of the locking mechanism is released by a pressing operation of the pressing operation member that is performed by an operator (user), so that the sheet storage portion is drawn. This image forming apparatus includes a spring that applies a force to the sheet storage portion in a drawing direction. Accordingly, when the lock of the locking mechanism is released, the sheet storage portion protrudes from the apparatus main body so as to be apt to be drawn (see Japanese Patent Application Laid-Open No. 2004-269147).
FIG. 13 is a plan view illustrating a part of an apparatus main body and a sheet storage portion in the related art, and FIG. 14 is an enlarged plan view of the vicinity of a locking mechanism illustrated in FIG. 13.
A force is applied to a sheet storage portion 807 in a drawing direction (a direction of an arrow A in FIGS. 13 and 14) by a spring (not illustrated), and the sheet storage portion is locked by a locking mechanism 809. A rotating shaft 880a is formed at the sheet storage portion 807, and a hook 880 is rotatable mounted on the rotating shaft 880a. Further, the hook 880 is rotated by the linear motion of a slide member 882 that is connected to the pressing operation member 804.
The apparatus main body of the image forming apparatus is provided with a positioning pin 881 to which the hook 880 is locked. The hook 880 is locked to the positioning pin 881, so that the protruding of the sheet storage portion 807 from the apparatus main body is regulated. Further, when an operator presses the pressing operation member 804 in a direction of an arrow B, the slide member 882 is pressed and moved in the direction of the arrow B and the hook 880 is rotated so that the hook 880 is disengaged from the positioning pin 881. Accordingly, the sheet storage portion 807 protrudes in the direction of the arrow A by the force of a spring (not illustrated).
Meanwhile, in the apparatus including the above-mentioned locking mechanism 809, the drawing direction (the direction of the arrow A) where the sheet storage portion 807 is drawn by a spring (not illustrated) is opposite to the direction (the direction of the arrow B) where an operator presses the pressing operation member 804. Further, at the point of the separation of the hook 880 from the positioning pin 881, a force of the spring (not illustrated) is applied to an operator's finger, which presses the pressing operation member 804, in the drawing direction opposite to a direction of a pressing operation. When the force of the spring (not illustrated) is applied to the finger, the operator can recognize that the lock of the locking mechanism is released.
However, since the force of the spring is set to a force that is required to draw the sheet storage portion 807, a strong force is suddenly applied to the operator's finger at the point of the release of the lock of the locking mechanism. Further, even though pressing the pressing operation member 804, the operator's finger is pushed together with the sheet storage portion 807 in the direction opposite to the pressing direction by the force of the spring that applies a force to the sheet storage portion 807. For this reason, there has been a problem in that the operator's operation feeling is bad.
Accordingly, the invention has been made in consideration of the above-mentioned circumstances, and provides an image forming apparatus and a sheet feeding device that improves operation feeling by allowing an operator to recognize the release of lock when a unit is drawn.